Compact Microstrip Lowpass Filter Using Stepped Impedance Spiral Resonator

In this paper, a dual-band band stop filter is applied based on a modified stepped impedance hairpin resonator in which, two open stubs are embedded in the structure. There are two transmission zeros in each stop bands. The center frequencies of the stop bands are placed at 2 and 5.92 GHz and their widths are 0.94 and 0.55 GHz, respectively. These stop bands can be adjusted by changing the dimensions of the embedded open stubs.